GCN Circular 30482
Subject
GRB 210722A: Swift/UVOT Detection
Date
2021-07-23T13:46:11Z (4 years ago)
From
Mike Siegel at PSU/Swift MOC <mhs18@psu.edu>
M. H. Siegel (PSU) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:
The Swift/UVOT began settled observations of the field of GRB 210722A
94 s after the BAT trigger (D'Avanzo et al., GCN Circ. 30475).
A source consistent with the XRT position is detected in the initial UVOT exposures.
The preliminary UVOT position is:
RA (J2000) = 01:48:07.28 = 27.03033 (deg.)
Dec (J2000) = -06:20:49.7 = -6.34713 (deg.)
with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence).
Preliminary detections using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:
Filter T_start(s) T_stop(s) Exp(s) Mag
white 94 244 147 14.31 +/- 0.02
v 637 656 19 14.52 +/- 0.06
b 563 583 20 14.65 +/- 0.04
u 308 557 246 13.68 +/- 0.02
w1 686 705 20 14.08 +/- 0.06
w2 4908 4971 62 17.08 +/- 0.14
The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.027 in the direction of the burst
(Schlegel et al. 1998).